Unusual response with tyrosine kinase inhibitor in small-cell lung cancer

Abstract

Abstract: The discovery of targetable mutations in non-small-cell lung cancer (NSCLC) has opened up a plethora of therapeutic options. Epidermal growth factor receptor (EGFR) mutations are found in 10%–20% of NSCLC; however, it is extremely rare in small-cell lung cancer (SCLC), and the efficacy of EGFR tyrosine kinase inhibitors (TKIs) in SCLC is unclear. Here, we describe the case of a 57-year-old nonsmoker lady who was diagnosed with metastatic SCLC. She received multiple lines of palliative chemotherapy. She was deemed unfit for further chemotherapy and immunotherapy and was started on tablet erlotinib empirically. On follow-up imaging with positron emission tomography-computed tomography, she had a partial response and has currently on erlotinib for 2.5 years without disease progression. Although cases with transformation of EGFR-mutated NSCLC to SCLC have been observed, de novo EGFR mutation in SCLC is infrequent. It has been observed that de novo EGFR mutation in SCLC is associated with females, non-smokers, and patients in the eastern part of the world. The current guidelines do not recommend molecular testing for EGFR mutations in SCLC. We described a case of SCLC who had a response to TKI and such cases warrant an answer to whether EGFR mutation testing should be recommended in nonsmoker, females with SCLC, or for them who have failed the first line of chemotherapy.